package com.guc.gutils;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * @Author: guc
 * @Description: 网络工具
 * @Date: 2021/6/28 11:54
 * @Version: 1.0
 */
public class NetUtil {
    public static final String IP_PATTERN = "\\d{1,3}.\\d{1,3}.\\d{1,3}.\\d{1,3}";

    /**
     * 获取外网的IP(必须放到子线程里处理)
     */
    public static String getNetIp() {
        InputStream inStream;
        try {
            URL infoUrl = new URL("http://2021.ip138.com");
//            URL infoUrl = new URL("http://www.baidu.com");
            URLConnection connection = infoUrl.openConnection();
            HttpURLConnection httpConnection = (HttpURLConnection) connection;
            httpConnection.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36");
            httpConnection.connect();
            int responseCode = httpConnection.getResponseCode();
            if (responseCode == HttpURLConnection.HTTP_OK) {
                inStream = httpConnection.getInputStream();
                BufferedReader reader = new BufferedReader(new InputStreamReader(inStream, "gb2312"));
                StringBuilder builder = new StringBuilder();
                String line = null;
                while ((line = reader.readLine()) != null) {
                    builder.append(line);
                }
                inStream.close();
                httpConnection.disconnect();
                String resp = builder.toString();
                Pattern p = Pattern.compile(IP_PATTERN);
                Matcher m = p.matcher(resp);
                if (m.find()) {
                    return m.group(0);
                }
                return "";
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

}
